1. Field of the Invention
Embodiments of the present general inventive concept relate to an image forming apparatus including a replacement component which is periodically replaced and is detachably mounted in a main body of the image forming apparatus.
2. Description of the Related Art
In an image forming apparatus such as a printer, a scanner, a copier or a multifunction printer, an initial replacement component which is initially used is provided during production, unlike a commercial replacement component.
For example, a development unit which is a replacement component of a color image forming apparatus may be divided into an initial development unit which is initially mounted in an image forming apparatus during manufacture thereof and a commercial development unit which is purchased and used by a user.
In general, the initial development unit may not include a Customer Replaceable Unit Monitoring (CRUM) memory to store information about the amount of toner used, in order to reduce material costs.
If the initial development unit does not include the CRUM memory, a user may purchase a commercial development unit and continuously perform printing, after purchasing an image forming apparatus and performing printing using toner contained in the initial development unit until the contained toner is used up.
Since the initial development unit does not include the CRUM memory to store the number of printed sheets, the image forming apparatus performs a hard stop operation such that printing is not performed using the initial development unit if the number of printed sheets exceeds a predetermined number. The hard stop operation is performed, for example, if a page count, a dot count, a photosensitive drum operation time, or a rotation time of a development roller in the development unit is greater than a predetermined limit value.
In order to perform the hard stop operation, information about the amount of toner used during printing is stored in a main controller unit. In the related art, the information about the amount of the toner used is stored in an Electrically Erasable Programmable Read-Only Memory (EEPROM) which is a non-volatile memory, thereby managing a replacement component. The non-volatile memory is widely used because a data value stored therein in advance is not erased even when the system power of the image forming apparatus is turned off.
However, when the EEPROM of the main controller unit is removed or data is accessed from a Central Processing Unit (CPU), a normal data value may be hacked using a hacking kit so as not to be transmitted.
A page count value, a dot count value and the like are stored in the EEPROM whenever printing is performed. At this time, the hacking kit may disturb “data writing” such that the data is not stored in the EEPROM. Alternatively, in a process of reading a data value stored in the EEPROM in association with the hard stop operation of the initial development unit so as to check whether a hard stop limit value has been reached, the hacking kit may change the data value to a normal value and transmit the changed data value to the CPU such that the CPU may not perform the hard stop operation due to such erroneous information. Thus, the initial development unit may be infinitely refilled.